Many electronic devices such as cellular phones, tablet computers, and the like have numerous input/output (I/O) interfaces that allow connectivity with other devices using one or more structural and communication protocol standards or, in some cases, proprietary standards. Such I/O interfaces make debugging the electronic devices by software engineers a fairly seameless task as the debugging tool can interface with the electronic devices using one or more of these common I/O interfaces, such RS-232, USB, etc.
Some electronic devices, however, have a limited number and type of I/O interfaces. A good example is portable audio players in which only an audio receptacle for receiving an audio plug (also known as an audio jack, stereo plug, mini-stereo headphone jack, microphone jack, etc.) may be provided. In these types of electronic devices debugging becomes much more challenging as the audio receptacle is typically designed to only carry audio signals (audio output from the device and, in some cases, microphone input). Debugging using a wireless communication technique is possible but also fraught with difficulties, including challenges arising from when the problems with the electronic devices arise from or interfere with the devices wireless communication circuitry, and challenges arising from wirelessly communicating with many devices arranged in close proximity to one another on an assembly line.
Some techniques for communicating data over an audio plug are known. These techniques typically call for data to be communicated from the electronic device via the audio output channels of the audio receptacle, and for data to be communicated to the electronic device via the microphone channel of the audio receptacle. That is, audio plugs include TS (tip-sleeve) connectors, TRS (tip-ring-sleeve) connectors, and TRRS (tip-ring-ring-sleeve) connectors, where ‘tip’ refers to an electrical contact being arranged at the tip of the audio plug, ‘ring’ refers to a ring contact being arranged next to the tip contact, and ‘sleeve’ refers to a contact being arranged at an end of the connector opposite the tip. For stereo audio, at least a TRS is generally required, as the tip and ring contacts are used for the left and right audio channels, respectively, and the sleeve contact is used as ground. To add a microphone channel, a TRRS connector is generally required, where the second ring contact is used for the microphone channel.
Accordingly, TRRS audio plugs may generally be used to communicate data via the microphone channel and one of the audio channels. However, there are continuing efforts to reduce the size of electronic devices, especially devices intended to be ‘portable’, and thus continuing efforts to reduce the size of the I/O interfaces included therewith. Since industry standards have evolved that effectively define the minimum lengths/spacing of tip, ring, and sleeve contacts of an audio plug, it may be extremely difficult and/or costly to incorporate a receptacle sized to receive a TRRS audio plug where the receptacle is both (a) compatible with the industry standards defined for the TRRS audio plug and (b) small enough to be effectively integrated into reduced size electronic devices. Thus, challenges arise when attempting to communicate data to and from an electronic device having a reduced-size audio plug receptacle as there is often insufficient space for the microphone contact that enables data to be communicated to the electronic device.